1. Field of the Invention
The present invention relates to a thermal pressure die for applying heat and pressure to a piece of trim cover assembly in the process for forming an automotive seat. More particularly, the invention is directed to a thermal pressure die which is operable to heat and press a piece of trim cover assembly into a desired uneven shape of trim cover assembly for automotive seat, or operable to heat and press a sheet of trim cover assembly against an uneven surface of foam cushion member via adhesive agent into a desired uneven configuration of bonded seat unit for automotive seat.
2. Description of Prior Art
Most of automotive seats are configured unevenly at their seating areas so that an occupant seated therein may feel a good and comfortable supportive touch. Typically, the automotive seat is so configured to have a central recessed area for supporting the buttock portion of the occupant and a pair of side bolster areas defined protuberant on the opposite sides of such central recessed area to support both lateral thigh portions of the occupant.
In general, in forming this sort of seat, a predetermined uneven shape of trim cover assembly, pre-formed by sewing together plural cover materials, is securely attached upon the corresponding uneven outer surfaces of foam cushion member.
As a means for forming the seat, there has been known a thermal pressure die device. The thermal pressure die device basically includes a lower stationary die and an upper die movable vertically to and from the lower stationary die, such that the upper die applies pressure and heat in a direction to the lower die. The die device per se may be arranged to form a trim cover assembly in an uneven shape corresponding to a predetermined outer uneven shape of seat, or to pressingly bond a trim cover assembly against an uneven surfaces of foam cushion member in conformity therewith, as required.
In both of those two kinds of thermal pressure dies, the trim cover assembly is subjected to a great pressure while being heated, which means that some local areas of the trim cover assembly are intensively expanded due to such great pressure and heat. This local expansion phenomena has been recognized as a cause for degrading a decorative outer surface layer of trim cover assembly which contains rectilinear decorative patterns, planar decorative patterns, solid decorative patterns with plural independent projections, a raised or gigged texture material, and so forth. Thus, it is highly possible that, upon being subjected to a great pressure and heat, a local portion of such delicate areas of trim cover assembly will be deformed to leave an objectionable point therein and impair the aesthetic appearance of resulting seat.
In view of the above-stated drawbacks, it is a primary purpose of the present invention to an improved thermal pressure die which permits for shaping a trim cover assembly for automotive seat into a desired uneven configuration while avoiding any deformation of the solid or projecting decorative surface of trim cover assembly.
To achieve such purpose, in accordance with the present invention, there is basically provided a thermal pressure die wherein a protection means of elastic and heat insulation property is provided on an uneven die surface of the die which is to be brought into pressing contact with a trim cover assembly.
Accordingly, the elasticity of the protection means absorbs an impact of pressure given from the die to the corresponding region of trim cover assembly, thereby reducing the pressure to a degree which avoids extremely forcible extension and deformation of the solidly textured surface of trim cover assembly, such as a raised or gigged surface, a solidly patterned surface with a great number of decorative projections, or geometrically patterned surface. Further, the heat insulation property of protection means serves to lessen a high temperature of heat heat insulation property of protection means serves to lessen a high temperature of heat imparted to the decorative surface of trim cover assembly, thereby protecting the same against deformation due to the heating.
Preferably, the protection means may comprise a protection element in a sheet form, which is fixedly attached on the uneven die surface. More preferably, such protection element be formed from a urethane foam material of about 2 mm thickness.
In one aspect of the invention, a projection adapted to form a decorative groove in the trim cover assembly may be formed on the uneven die surface such as to surround a part of that particular uneven die surface, and the protection means be provided on such particular part of uneven die surface surrounded by the projection.
Other features and advantages of the present invention will become apparent from reading of the description hereinafter with reference to the annexed drawings.